servo madness


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    Default servo madness

    Hello friendsservo madness-6-jpg
    I purchase the power supply drivers and servos as a complete setup from a military simulator


    power up and able to control the motors with consol and dac 1000 and dac 0

    I was following along the thread frankenstein from a couple years back and then worked the kanalog instructions but am going in circles

    anyone with an idea for setup that could give predictable solutions

    pictures to follow in a minuteservo madness-81-jpg

    Similar Threads:
    Last edited by jensenjim; 02-11-2019 at 01:57 PM. Reason: add pix


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    Member TomKerekes's Avatar
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    Default Re: servo madness

    Hi jensenjim,

    Please post screen shots of a Move on the KMotion Step Response Screen and we can likely help. Also include your IIR Filters and Config/Flash Screens so we can see all your settings. You can make a screen shot by Alt - Print Screen then paste to Paint.exe and save as a .png file. It helps to also post the raw data as a text file so we can view plots as other plot types and zoom in to see details. Work on one axis at a time.

    You might clean KFLOP/Kanalog

    Regards
    TK http://dynomotion.com


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    Default Re: servo madness

    servo madness-screenshot-7-jpgservo madness-screenshot-10-jpgservo madness-screenshot-11-jpg


    the encoders have z wires, i orignally had them connected to jp2 but disconnected them, my reading left me to believe they were not needed. I have a install quide for the amc driver i studied , there is some info on voliciry integerator mode may need tach input. this just leaves me confused on the wiring. is there somewhere to hook up and enable the z wires? also reading about the driver modes is a bit confusing, most says put the driver in velocity mode

    servo madness-screenshot-12-jpg


    when i started i copied another post setup and it looked like things were moving in the right direction. then after acouple days reading and experimenting it all went south
    right now it looks like things are stable but no movement with move or step but can control drives from console i will need to run two drives on x axis also i still have another driver and servo to hook up. I was not sure if this setup was goin g to work, they are stout servos, I had prevously bought steppers and the stepper driver from dynomotion, i also got geko drivers , 5 yrs later i am banking on the servos, I lost the kstep board so kanalog is my option

    Last edited by jensenjim; 02-11-2019 at 05:52 PM. Reason: text


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    Default Re: servo madness

    servo madness-screenshot-13-jpg


    i adjusted the driver ref in gain and was able to move the red line. at this point all step commands did not move the servo
    I was coping the lanalog webpage settings

    Last edited by jensenjim; 02-11-2019 at 11:22 PM.


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    Default Re: servo madness

    Hi jensenjim,

    I think the main issue now is the Input and Output Gains are 0. That is like turning off the encoder input and the DAC output. Nothing will move and even if it did nothing would be observed to move. Set both to 1. If the motor runs away the wrong direction try one set to -1.

    As I asked in the last email please work on one axis at a time. Once you learn how to tune one axis you should be able to tune all your axes the same way later. Showing only partial information from multiple axes only adds confusion.

    Your screen shots are too blurry to read. Please improve your screen captures. As I mentioned Alt-PrintScreen will capture a single screen rather than the whole desktop,

    You didn't save and attach the raw data as a text file.

    Use the "Move" button not the "Step" button.

    Never enter 0 for Velocity, Acceleration, or Jerk. Its impossible to move without some of each. That like saying drive your car but you are not allowed to move at any speed (Velocity), you are never allowed to depress the gas pedal (Acceleration), or you are never allowed to change the gas pedal's position (Jerk).

    there is some info on voliciry integerator mode may need tach input. this just leaves me confused on the wiring.
    It doesn't look like there are tachometers and the tachometer input seems to be wired to GND. So the amplifier will probably be operating in torque mode regardless.


    is there somewhere to hook up and enable the z wires?
    I wouldn't be concerned with Z signals for now. (I assume those are encoder index pulses).

    Regards
    TK http://dynomotion.com


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    Default Re: servo madness

    servo madness-1kflop1-jpg


    I am having issues with computers and cameras , keyboards etc. This is a image to get an idea of whats happening.
    tomorrow I will read some more on the kanalog help and get a better imageing system so I can post better quality



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    Member TomKerekes's Avatar
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    Default Re: servo madness

    Hi jensenjim,

    Please don't take photos of the screen with cameras. Instead capture the window by:

    #1 select the window of interest
    #2 hold down the ALT key
    #3 push the Print Screen Key
    #4 open Paint.exe
    #5 click Paste
    #6 click Crop
    #7 File | SaveAs
    #8 Image.png

    I think you have classic positive feedback runaway. See here.

    HTH

    Regards
    TK http://dynomotion.com


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    Default Re: servo madness

    servo madness-2-pngservo madness-1-jpg

    ok I tried - gain is this moving in the right direction


    servo madness-3-png

    Last edited by jensenjim; 02-12-2019 at 11:31 AM.


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    Default Re: servo madness

    Hi jensenjim,

    Yes, congratulations, that looks to be now working like a servo!

    It would be helpful if you put more effort into your responses so we could tell what parts of the process you are understanding.

    Can you see that your amplifier is operating in Torque mode because the Output (green) corresponds to acceleration (curvature) in the Position (red) plot?

    Torque servos require some Derivative Gain to be stable. Please read this wiki article and add some D Gain.

    Regards
    TK http://dynomotion.com


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    Default Re: servo madness

    ok , my caution is to expose my ignorance. I am a motor head with half a brain but I get there. My head has been swimming reading both the dynomotion help, the amc servo driver info I have and forums.
    so what you are saying is the green line powers up the move then powers down. Part of my problem is the intial settings on the servo driver, i think that is settling down, for a while i encountered growling and bucking from the servo
    so I will read more and put some D gain, so glad you didn't instruct me again on screen capture. My computer setup is a mixed bag of crap, some military throw away with a mac keyboard. my intent is to determine if I can use this servo setup befor I
    throw any more dollars at it. I thought building the table was hard but this is extreme brain torsion. I love this sruff but it can be frustrating, crazy hours spent learning, guess its better than css and php

    d gain max

    servo madness-4-jpg



    is it a goal to smooth out the red line?

    reading wiki (Make sure when testing the size of move is long enough for full acceleration and velocity are achieved. A common mistake is to have Acceleration or Velocity Settings set to too high for your system but when testing a short move there is no indication of a problem. The plot mode of Velocity Output vs Time can be helpful to verify full Velocity is being achieved.

    The idea is that a motor axis has torque and speed limitations and you should determine and understand what they both are for your system. Available motor torque drops off with higher speed. At some speed the motor will not even be able to generate any torque at all. Motor torque is required to accelerate the axis. We need to make sure that no combination of velocity and acceleration will ever cause the axis to fault/stall/fail. So there is often a complex set of speeds and accelerations that will work ok that form an envelope of workable speed and acceleration)
    I conclude I need to have the servos under the operating load to get the tune right

    am I ok to proceed with this or is more tuning needed befor that

    Last edited by jensenjim; 02-12-2019 at 06:02 PM.


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    Member TomKerekes's Avatar
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    Default Re: servo madness

    Hi jensenjim,

    Sorry for the delay. I don't get notified if you edit posts only if you make a new post.

    d gain max
    I don't understand what you mean by this. The image shows the D Gain still at zero. I don't see any change from previous plot. Did you change anything?

    is it a goal to smooth out the red line?
    Basically yes. The red line should follow the blue line perfectly. On a well tuned system you can not typically see any difference on this plot type and scale. You would need to zoom in (left mouse click drag), or change the plot type to plot error (which is the difference between the red and blue lines). That is why I asked you to save and post the raw data so w can re-plot it ourselves. But at this point it isn't necessary to see the error.

    I conclude I need to have the servos under the operating load to get the tune right
    Not really no. If it is already performing this poorly without load it will likely be worse under loads.

    am I ok to proceed with this or is more tuning needed befor that
    The system is still poorly tuned with no D Gain or Filters.

    HTH

    Regards
    TK http://dynomotion.com


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    Default Re: servo madness

    hello and thanks for the help
    I have come to the conclusion that there is no practical guide to follow that explains how this system works.
    I had high hopes I could get these servos working, I have them installed completely now, 4 axis, channel 0 and 1 to follow 0.
    at this point I give up. I have tried to copy other posts to make any scense of kflop and there is nothing available that i can understand.
    I will trash this setup and try to install stepper motors and a controller that i can configure



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